Priority is claimed to Korean Patent Application No. 00-46345 filed on Aug. 10, 2000, here incorporated by reference
1. Field of the Invention
The present invention relates to a resonator, and more particularly, to a resonator in which a cavity is filled with a predetermined material.
2. Description of the Related Art
A resonator has been usually used as a tuning circuit in an antenna, a filter, a duplexer, communication appliances or electric appliances.
FIG. 1 is a separated perspective view illustrating a conventional resonator and FIG. 2 is a cross-sectional view of the resonator shown in FIG. 1 when combined.
Referring to FIGS. 1 and 2, the resonator includes a lower substrate 11 having a rectangular groove 12 and an upper substrate 16 that is combined with the lower substrate 11 to form a cavity 13.
The inner wall of the rectangular groove 12 on the lower substrate 11 is coated with a conductive thin film 14.
A strip line 17 for a wave-guide and a conductive thin film 19 having a partially cut slot 18 are formed on the upper surface and lower surface of the upper substrate 16, respectively.
The conductive thin film 19 is combined with the rectangular groove 12 to form the cavity 13.
A pole 20 connects the strip line 17 with the conductive thin films 14 and 19.
Resonators having the above-described structure are manufactured by semiconductor minute processing techniques. However, a resonance frequency of a cavity resonator is inversely proportional to the size of the cavity 13 rendering it too large to employ in many portable communication terminals, e.g., ones using a frequency of 2 GHz, which are being increasingly miniaturized.
To solve the above problem, it is an objective of the present invention to provide a resonator whose resonating structure corresponding to a resonance frequency can be reduced.
Accordingly, to achieve the above objective, there is provided a resonator including a lower substrate having a groove, a dielectric filling the groove, a material film which is formed on the inner wall of the groove and prevents permittivity from suddenly changing between the lower substrate and the dielectric, an upper substrate which is combined with the lower substrate thereby forming a cavity, a conductive thin film formed on the lower surface of the upper substrate to face the dielectric and having a slot in contact with the material film and exposing the dielectric, and a strip line for a wave-guide formed on the upper surface of the upper substrate and connected to the conductive thin film.
Here, the dielectric is composed of first and second dielectrics that have larger permittivities than air, and the permittivity of the first dielectric formed on the second dielectric is smaller than that of the second dielectric.
The material film is a dielectric film that has the permittivity between that of the dielectric and that of the lower substrate and is made of a paraffin film or a grease film.
Also, to achieve the above objective, the resonator includes a lower substrate having a groove, a magnetic material filling the groove, a material film which is formed on the inner wall of the groove and prevents permeability from suddenly changing between the lower substrate and the magnetic material, an upper substrate which is combined with the lower substrate to form a cavity, a conductive thin film formed on the lower surface of the upper substrate to face the magnetic material and having a slot in contact with the material film and exposing the magnetic material, and a strip line for a wave-guide which is formed on the upper part of the upper substrate and is connected to the conductive thin film. The magnetic material is made of first and second magnetic materials.